2 Jobs Dilemma.

 First off, this is a nice 'problem' to have in an industry with very few openings. Look on the bright side.

If you were to take just the well-paying job all the issues you mention would fall away. You would be able to bring 100% of your focus to it and so manage it better. The guilt about your peers not having similar opportunity would lessen or disappear; as should imposter syndrome. Since the job is prestigious and career-enhancing, it could lead to more chances of getting the type of jobs that you find interesting. So you wouldn't really be foregoing the interesting job now, but pushing that opportunity into the future.

If you're now committed to doing both jobs and can't really decline the interesting one, consider 'hiring' help  by sub-contracting part of it to one of your peers. That way, you can retain some involvement but not spread yourself too thin over 2 jobs.

If you are committed to both jobs then be strict with yourself as far as time / project management is concerned. And make a mental note that you'll 'pay it forward' to your peers whenever an opportunity arises eg. by giving a referral.